Distinguishing the "updating" component of working memory

A memory system must be able to serve at least two functions, to hold information over time, and to change the information that is being held. While several studies have identified a vast cortical network to be involved in working memory, little work has tried to distinguish the two different functions.

In 2008 I came into contact with Patrick Sörqvist, then a PhD student from an applied psychology lab in Gävle, Sweden, who was interested in practical implications of memory systems. He wanted to run an fMRI study of the number updating task, which can distinguish the points in time when working memory content is being updated, as opposed to when the content being held constant while ignoring new information. I helped out with experiment design, programming, fMRI analysis and write-up. We found some cortical regions to be more activated for memory updating than when not updating, and other regions to be activated in the inverse condition.

Sörqvist & Sætrevik (2010) The neural basis of updating: Distinguishing substitution processes from other concurrent processes - Scandinavian Journal of Psychology

We probably used the wrong heatmap shading for the fMRI activations shown in Figure 1 and 2, as they did not come out well in the black and white print. They were supposed to look more like this:

Figure 1: Areas more activated when updating.

Figure 2: Areas more activated when not updating.

Here are the same activations shown in an animated glass brain. Areas more activated when updating are shown in "hot", areas more activated when not activated are shown in "cold" (t-values 6-16 are shown).

The study had quite few participants, but we later supported the main finding in another study with more participants (currently under review).